The auxiliary verb to do is employed: 
1. To express the emphatic form of the verb; as 
I do call, l did call. 
2. To complete the interrogative form of the verb in the simple 
tenses only. 
Do you call? (not: Call you) Did you call? 
3. To avoid the repetition of the principal verb. 
Do you offen call on Mr. N. ?■ Oh yes, I do. 
4. In all simple negative phrases. 
/ do or did not call. 
To do is not employed: 
1. When an interrogative pronoun forms the subject of the sen- 
tenee. 
Who calls you? Wh ich hook interests you? 
but Whom do you call? Which hook do you wish to buy? 
2. In compound tenses; as 
Jlas he called? Ile hass not called. 
Will he call? They roill not call. 
Conjugation. 
Indicative Mood. 
Present Tense 
I, you do 
he does 
ree, you, they do 
Infinitive to do 
Participle Present doing 
Only the present and past 
used as the auxiliary. 
Past Tense 
I, you did 
he did 
we, you, they did 
Imperative do 
Participle Past done 
tenses indicative of to do are 
Conjugation of the verb to call. 
Infinitive Present to call Participle Present 
Infinitive Past to have called Participle Past 
Participle Perfect 
Indicative Mood. 
callin g 
called 
having 
called. 
Present Tense 
I, you call 
he, she, it calls 
we, you, they call 
Past Tense 
I, you called 
he, she, it called 
tue, you, they called